Cairhien is one of the Nations of the New Era, southeast of Tar Valon and situated between the River Alguenya and the Spine of the World. Cairhien's capital is the city of Cairhien, which is a major port on the Alguenya, which flows south to Aringill where it joins the longer Erinin and then to Tear and the Aryth Ocean. Its strategic position is the gateway to the Aiel Waste via the Jangai Pass and as a major factor in river trade with Tear has allowed it to flourish and Cairhien to be a moderately rich nation. That posistion has also worked against Cairhien, as the Aiel have invaded it twice, doing great damage to the capital city and surrounding areas.

Before Tarmon Gai'don, the Dragon Reborn gained Cairhien in his conquest but the Last Battle, he appointed Moraine Sedai as Queen of Cairhien along with her former gleeman husband, Thom.